Apparatus for preventing leakage from open ended mixers or agitators



Sept. 1, 1959 L. E. BROBERG 2,902,263

APPARATUS FOR PREVENTING LEAKAGE FROM OPEN ENDED MIXERS 0R AGITATORS Filed Feb. 11, 1957 INVENTOR. Leouaao E. Baoaene ATTORNEY United SttcS- Patent APPARATUS FOR PREVENTING LEAKAGE FROM OPEN ENDED MDGERS OR AGITATORS Leonard E. Broberg, Milwaukee, Wis., assignor to The T. L. Smith Company, Milwaukee, Wis., a corporation 'of Wisconsin Application February 11, 1957, Serial No. 639,328 1 Claim. (Cl. 259-461) This invention relates to open end transit mixers or agitators and particularly to prevention of spillage from the center of the charging cone.

The desire to reduce the Weight of transit mixers to thereby permit an increase in the pay load has led to the introduction of the open end mixer. The blades on the interior of the drum work the load forward in the drum when the drum is rotated in the mixing direction and tend to prevent leakage through the open end of the drum. However, since the load may be increased, the concrete gets well back in the charging cone which does not have blades. This leads to leakage from the cone unless the charging hopper seats on the cone to seal the opening. This solution requires expensive bearing and seal structures which are desirably avoided. The present structure avoids the bearings and seals and acts to prevent leakage from the cone. The present structure is fully compatible with a moving charging hopper or chute although it can be used with a fixed chute.

The principal object of this invention is to provide a simple, inexpensive structure for preventing leakage from the charging cone.

Another object is to provide a leakage preventing structure which can be used with a movable charging hopper and does not entail added care or operation by the operator.

Other objects and advantages will be pointed out in, or be apparent from, the specification and claim, as will obvious modifications of the single embodiment shown in the drawings in which:

Figure 1 is a rear view of a transit mixer according to this invention; and

Figure 2 is a fragmentary side elevation with parts broken away to show the details of the present structure.

Referring to the drawings now in detail, truck frame is provided with an inverted, U-shaped chanel frame member 12 to which brackets 14 are welded for interconection by inverted angle iron 16. The angle iron is provided with bearing supports 18 which journal shaft 20 on which the chute brackets 22 are journalled for movement about the axis of shaft 20 as the linkage 2426 is actuated by hand wheel 28 to move the chute hanger arms 30 pivotally connected to the chute 32 through the laterally projecting arms 34. This type of structure is rather conventional and forms no part of this invention except so far as it discloses a movable chute. Greater detail of a similar arrangement may be seen in Rockburg Patent No. 2,563,963.

Drum 36 is rotatably mounted in the frame for rotation about an upwardly and rearwardly inclined axis such as customarily employed in the high discharge type of mixer. The rear end of the drum is open and has a charging cone 38 mounted therein centrally of blades 4042. These blades spiral throughout the length of the drum and serve to work the load forward of the drum when the drum is rotated in the mixing direction and to work the load to the rear of the drum for discharge when drum is rotated in the discharge direction.

ice:

Mounting bracket 44 is welded to angle iron 16 (as may be seen in Figure 2) and supports a generally tubular metal bib member adjacent the rear opening of the cone 38. The bib member includes a bib portion 46 which projects into the cone and overlaps the lower portion of the cone for a substantial distance. This may be seen in Figure 2. When the bib member is properly mounted the clearance between the cone 38 and the bib portion 46 is quite small and prevents any leakage. Thus, any leakage which would tend to occur would have to occur through the tubular portion of the bib member and out through the opening at the rear of the bib member. It will be noted that this opening is surrounded by an annular flange presenting a rearwardly facing seal ring or lip 48 against which a cooperating flange formation carried by the swingable chute 32 seats as shown in Figure 2. When the chute is so seated, the bib member forms a continuation of the inside surface of the chute and serves as an extension of the chute. With the chute seated on the bib flange 48 any leakage which might tend to occur would merely occasion a build-up of material in the chute. The level of the load carried in the drum would not be expected to rise above the mid point of the rear opening.

When hand crank 28 is actuated the charging chute 32 can be swung out to the position shown in dotted lines in Figure 2 to permit access to the interior of the drum for inspection or cleaning purposes. It will be noted that the bib member remains in position under these conditions and there is no problem of getting the bib portion 46 out of the charging cone. There is no bearing problem between the bib member and the hopper since both are non-rotatable. Since the bib portion 46 actually clears the interior of the cone, there is no bearing problem at that location. Any clearance remaining would, of course, tend to be somewhat filled by concrete but if this should build up to a point where it would tend to hinder rotation, the material would be merely ground away without any appreciable damage to the metal parts.

From the above it will be appreciated I have provided a very simple, long wearing arrangement for preventing spillage from centrally of the charging cone on an open end transit mixer or agitator. This has been accomplished without any sacrifice in the usefulness of the mixer. By this it is meant the mixer may still be provided with a swinging charging chute to permit ready access to the drum interior. It 'will, however, be appreciated that the hopper could be permanently fixed with respect to the bib member if the swinging feature was not deemed important.

Changes in the present structure will undoubtedly occur to those skilled in the art. For that reason, the scope of the invention is to be limited only by the scope of the claim rather than being limited to the illustrated form of the invention.

I claim:

The combination with a mixer or agitator of the type having an open ended drum rotaatbly mounted in a fixed frame, the drum having spiral blades on the interior thereof, a charging cone central of the blades adjacent the open end of the drum, of means for preventing spillage from centrally of the drum, comprising a nonrotatable bib member fixed to the frame rearwardly of the open end of the drum, said bib member including a central tubular portion provided with a bib portion projecting forwardly therefrom into the charging cone and overlying the lower portion of the inner surface of the cone to prevent spillage from the drum, the rear outer end of the tubular portion of the bib member having a rearwardly facing annular seating flange, and a charging chute movably mounted on the frame for outward and upward swinging movement with respect to the bib member, said eharging chute having a forwardly facing seating flange formation adapted to seat on the seating flange of the bib member when in drum charging position.

UNITED STATES PATENTS Smith Sept. 18, 1956 

